Analysis of optical fiber failures under bending and high power

Glaesemann, G. Scott; Chien, Ching-Kee; Clark, Donald A.; Coon, Jeffery; DeMartino, Steven E.; Logunov, Stephan L.

doi:10.1117/12.555267

Cited by 2 publications

(7 citation statements)

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“…It is well known that failures at bends in an optical fiber are caused by light leaking from the core when the fiber is accidentally bent tightly with a high power input [29][30][31][32][33][34][35][36][37]. Two kinds of failure regimes have been classified by Sikora et al, which they named regime 1 (R1) and regime 2 (R2) failures [31].…”

Section: Introductionmentioning

confidence: 99%

“…Two kinds of failure regimes have been classified by Sikora et al, which they named regime 1 (R1) and regime 2 (R2) failures [31]. Among them, R1 failure will lead to the catastrophic failure of the fiber and burning of the coating [32,37]. As the transmittance of the coating material is not 100%, the leaked light is somewhat absorbed and heat occurs in the coating.…”

Section: Introductionmentioning

confidence: 99%

“…Heat generated in the coating material by absorbing an optical power will be transferred to the neighboring cladding (silica glass) layer. When the temperature of the silica glass reaches higher than 1,100°C (= 1,373 K), the glass will soften and viscously deforming of the glass will occur [31,32]. The fiber at the heating part will begin to kink sharply after the viscous deformation of the glass and the catastrophic failure of the fiber will occur.…”

Section: Introductionmentioning

confidence: 99%

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Bending Induced Temperature Increases in Double-Clad Fibers for High-Power Fiber Lasers

Shuto¹

2022

JEEE

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Rare-earth-doped optical fibers are one of the most promising solid-state lasers. In these fiber lasers, a cladding-pumping scheme using large-mode-area double-clad fibers (DCFs) is utilized to increase the overall conversion efficiency of pumping light and to overcome the restriction owing to the onset of stimulated Raman scattering. On the other hand, it is extremely challenging to increase the fiber core size while retaining the excellent beam quality because fibers with large core size allow propagation of several higher-order modes (HOMs), except for the fundamental mode (FM). In order to suppress HOMs, DCFs are bent with a relatively small bend radius. Failures at bends in an optical fiber are caused by light leaking from the core when the fiber is accidentally bent tightly with a high power input. For the DCFs with core radii of 10 and 20 µm, the relationship between the bending induced temperature increases and the bend losses in the bent DCFs was investigated theoretically by the explicit finite-difference method using the thermochemical SiO x production model. The temperature at the boundary between the inner and outer cladding layers increased with increasing optical power P at 1.080 µm and was a large value higher than the softening temperature T s of the silica glass when P = 5 kW was entered to the bent DCF with a bend radius R of 150 mm and a core radius of 10 µm. On the other hand, the temperature at the boundary was a small value lower than the T s when P = 10 kW was entered to the bent DCF with a large R of 245-275 mm. Furthermore, it was found that the initiation of the fiber fuse was fairly easy under a certain conditions where the temperature at the boundary was higher than the T s .

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bending Induced Temperature Increases in Double-Clad Fibers for High-Power Fiber Lasers

Shuto¹

2022

JEEE

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“…An extensive range of publications has described coaling damage and fiber failutr mechiaisms when high power is 1aunched into tightly bent fibers [1][2][3][4][5]. This issue ais been raised because of the potentiality of distributed Raixan amplification in transmission systems [6 7] and the occurrence of unwanted weak points in the network, such as tight bending or contanirnalion at connector endface for instance.…”

Section: Introductionmentioning

confidence: 99%

“…It is commnonl assumed that damage at fiber bends is driven by an increase of teemperature when power lost at the bend is absorbed by th coaling. Relalionship between launched power, bend diamneter and time to failure ca:n be established in severe operaling conditions [1,[3][4][5]. It eiables to measure fiber mpture or coating damage within a "reasonable" time range.…”

Section: Introductionmentioning

confidence: 99%